It has become common practice to mount a spreader upon a vehicle for spreading particulate material, such as salt and cinders, onto a roadway being travelled by the vehicle. One of the more common spreaders employs a hopper having a lower discharge opening through which the particulate material falls onto a rotating spreader element, known as a broadcast spreader. By rotating the spreader element as material is being discharged onto the element, the particulate material is centrifugally propelled by the spreader element in a wide pattern onto the roadway. In more recent designs of this type of device, a motor is mounted on the spreader and below the rotating spreader element for directly rotating the spreader element. In some instances, the spreader element is supported on a motor driven shaft which protrudes upwardly into the hopper. This shaft includes outwardly extending members which are used to break up large agglomerations of material and to agitate the material for better feeding through the discharge opening. In some instances, this type of material spreader includes a valving mechanism between the discharge chamber and lower spreader element. When not in use, the valving mechanism is often closed. When in use, the valving mechanism is opened to allow discharge of material through the discharge opening and onto the broadcast spreader. Such a mechanism is illustrated in U.S. Pat. No. 3,374,956, which is incorporated by reference for background information. A spreader structure as illustrated in the above-mentioned patent presents some difficulties in that the valving mechanism must be closed by external mechanisms, such as rods, cables, links, etc., which can become clogged with snow and ice during use of the spreader. The adjustment of externally manipulated elements is critical, especially when the hopper is movable with respect to the supporting vehicle. In addition, external control devices require more time to assemble onto a vehicle and require adjustments of the valve moving elements for accurate control of the valving mechanism.